The low prevalence of moderate-to-vigorous physical activity (MVPA) among adult Latinas likely contributes to the high rates of cancer and other chronic diseases in this population. The goals of the current study, based largely upon the core principles of the Social Ecological Model, are to design, implement, and evaluate an innovative multi-level intervention promoting physical activity among churchgoing Latinas. Given the central role of churches within the Latino community and their overall commitment to the well-being of their members, churches serve as the ideal setting for the current study. The evidenced-based intervention will target three tiers of environmental influences (i.e., church, immediate neighborhood surrounding the church, and community) on activity, as well as MVPA-related personal factors (i.e.., intra/interpersonal, cultural, and perceived environmental variables). The physical activity intervention will be compared with an attention-control condition targeting general topics related to cancer prevention and control. Sixteen churches will be randomly assigned to either the physical activity intervention or the attention-control condition. Approximately 432 Latinas who attend church services at least weekly will be recruited as participants from the sixteen churches. Outcome analyses will determine whether the multi-level intervention will increase MVPA among Latina churchgoers in the intervention condition relative to the attention-control condition. The study's primary outcome will comprise accelerometry-measured MVPA at baseline, 12 and 24 months following implementation of intervention activities. Intra/interpersonal mediators and cultural moderators, as well as environmental mediators and moderators will be measured to assess multiple levels of influence on Latinas' physical activity. The proposed group - randomized controlled trial builds on formative and pilot research findings funded by an NCI R21 to the Principal Investigator, as well as more than 2 decades of foundational work by the research team. In the R21, the promotoras realized individual and environmental level changes. To examine the effectiveness of the multi-level intervention on Latinas' PA, a randomized controlled trial is an essential and logical follow-up to the pilot study. PUBLIC HEALTH RELEVANCE: Increasing physical activity rates in underserved communities will likely help reduce racial/ethnic disparities in chronic disease rates. Findings from the current group randomized trial could shed light on factors that inhibit/facilitate physical activity in Latino communities. Furthermore, the results from the intervention trial could improve approaches to promoting a healthy lifestyle in Latinos.